1. Field of the Invention
This invention relates generally to methods and apparatus for sampling hazardous materials, and more particularly, to a method and apparatus for extraction and removal of cored samples of hazardous material and airborne particulates, vapors, and fumes which significantly reduces the release of hazardous materials to the atmosphere.
2. Brief Description of the Prior Art
Unprotected exposure to asbestos (including tremolite, anthophyllite and actinolite) is known to cause such fatal diseases as asbestosis, lung cancer, and mesothelioma. Construction materials containing these substances have been used extensively in schools, public buildings and private residences for over 50 years. The Federal Government as well as many state and local governments have set standards for allowable exposure to asbestos and testing for asbestos-containing materials (ACM) is required in schools and many public buildings.
Asbestos may be found in cement products, acoustical plaster, fireproofing textiles, wallboard, ceiling tiles, thermal insulation, floor tiles, roofing shingles and other materials widely used in the construction industry. Friable ACM has been grouped into three categories: (1) sprayed-on or troweled-on materials on ceilings, walls and other surfaces; (2) insulation on pipes, boilers, tanks, ducts, and other equipment; and (3) other miscellaneous products which are mostly nonfriable.
As awareness of the magnitude of asbestos content in building materials increased, a public demand for identification and evaluation through sampling followed. Accepted methods for removing samples of ACM for laboratory analysis involve the investigator removing the sample (often atop a ladder) with a knife or coring tool and placing the sample in a plastic bag. Since data available to date provide no evidence for the existence of a safe level of exposure, the prudent investigator must make every reasonable attempt to minimize, if not eliminate, exposure to the asbestos fibers. Therefore, for sample collection, a high efficiency respirator is worn by the investigator as well as disposable, protective clothing.
Because the prior art sampling techniques are substantially hazardous to unprotected building occupants, it is most often desirable to perform the sampling operation outside of normal hours of occupation. However, even with the greatest of care during sampling, asbestos exposure to the building occupants is probable since the disturbed fibers are carried throughout the building by air currents and remain in the system for extended periods of time.
The method and apparatus described herein provide a means by which samples of hazardous materials such as friable ACM can be removed safely under a high efficiency particulate air (HEPA) vacuum blanket. The airborne particulate material, vapors, and fumes are removed from the air by the invention and filtered from the air as the sample is taken and the sample container is sealed under the same vacuum blanket. The hazard of the materials to the investigator and building occupants is eliminated. The samples can be taken conveniently, during normal working hours without the use of special breathing devices or protective clothing.
There are several patents which disclose apparatus and methods for taking samples of various materials.
Johnson, U.S. Pat. No. 1,416,354 discloses a vacuum sampler for liquids comprising a cylindrical housing having an interior tube with an open bottom. The top of the housing is attached to a tubular member having a vent cock in the line. The device is lowered to the desired depth in a body of liquid and then the vent cock is opened causing the liquid to flow through the tube and into the housing.
Hintermaier, U.S. Pat. No. 3,383,839 discloses a vacuum device for collecting fibrous materials such a paper fibers. The patent is directed toward a clear plastic tubular member installed in a vacuum cleaner hose having one end attached to a vacuum cleaner. The other end of the hose is connected to a scraper/collector head. A wire mesh filter member is removably carried in the clear tubular member to capture fibers loosened by the scraping head.
McAndrew, U.S. Pat. No. 2,666,330 discloses a coring device for baled goods such as wool. The device comprises a cylindrical housing with a depending tubular coring tube having a removable cutting tip. A removable inverted can or receptacle is carried in the housing in communication with the coring tube and is retained in position by a resilient pad of sponge rubber on the floor of the housing. The coring tube is placed on a bale of wool and rotated to collect sample material in the receptacle.
Barton, U.S. Pat. No. 3,225,602 discloses a balance chamber for deep sea coring which is connected to a core barrel. The balance chamber has a lesser internal pressure than is exerted on the core barrel which has penetrated the ocean floor. The balance chamber can be suddenly opened to the core barrel by a valve creating a pressure imbalance which causes the movement of the sample material into the core barrel.
Herkness, U.S. Pat. No. 4,498,547 discloses an earth sampling tool comprising a sample bottle housing at the end of a rod which has a depending cone shaped probe. The removable sample bottle is inverted and compressibly retained in communication with the cone shaped probe by resilient material at the throat and bottom of the bottle. A sample is taken by pressing the probe into the soil.
The present invention is distinguished over the prior art in general, and these patents in particular by a sampling nozzle operatively coupled to a vacuum device and having a tubular coring member removably mounted at its upper end for extracting a sample of material suspected of being hazardous. A canister is removably carried in the nozzle beneath the coring member in co-active, in-feed relation therewith for receiving the extracted sample of material. Air passages through the nozzle sidewall cooperate with a conical shroud carried on the upper end of the nozzle to create a blanket of air vacuum surrounding the coring member and the area around which the sample will be extracted. A high efficiency particulate filter may also be provided between the nozzle and the vacuum device.
The sample is extracted while the surrounding blanket of air vacuum is active by placing the sampling nozzle against the goods to be sampled with the coring member in firm contact with the surface of the goods and pressing the nozzle to cause the coring member to penetrate the material. The blanket of air vacuum surrounding the coring member draws airborne particulate material, vapors, and fumes in the vicinity of the extracted sample into the nozzle to be filtered. The cored sample falls through the coring member into the canister. Under the surrounding vacuum blanket, the coring member is removed, and the canister is ejected partially outward of the nozzle and it is capped to sealingly contain the extracted sample of material afterwhich it may be safely transported to a convenient location for further analysis.